This project will deal with the localization and characteristics of purine phosphoribosyl transferases, 5'-nucleotidases and purine ribo-nucleoside kinases in the trypanosomid (kinetoplastid) flagellate, Crithidia fasciculata. Transport of purines across the cell membrane of Crithidia will be studied, using 14C-labeled compounds. BIBLIOGRAPHIC REFERENCE: Kidder, G.W., Dewey, V.C. and Nolan, L.L., Enzymes of the orotate biosynthetic pathway in Crithidia fasciculata. Can. J. Biochem., 54, 32 (1976).